Cooling or preheating device for coarse or bulky material with heat space recovery equipment

ABSTRACT

An apparatus for treating material in bulk. An upright bunker is provided to accommodate the material in bulk while it flows gravitationally down the interior of the bunker. The bunker has at its lower discharge end a tapered wall formed with apertures to admit to the material in the bunker a gas at a temperature different from the material of the bunker while permitting those parts of the material which are small enough to pass through the apertures to fall out of the bunker through the apertures before reaching the lower discharge end. A plenum surrounds the apertures and communicates with a gas supply through which the gas is delivered to the apertures to flow therethrough, and a gas discharge communicates with the top of the bunker to discharge the gas therefrom. The material falling through the apertures is collected in the plenum and conveyed away from the latter. Where the gas flowing up through the material in the bunker is heated by the latter material, a boiler may receive the hot gas from the bunker to use the gas for generating steam, and the gas which is cooled in the boiler is then returned to the plenum.

United States Patent [191 Kemmetm-ueller COOLING OR PREHEATING DEVHCEFOR COARSE OR BULKY MATERIAL WITH HEAT SPACE RECOVERY EQUIPMENT RolandKemmetmueller, Carlton House, 550 Grant 30, Pittsburgh, Pa. 13540 [22]Filed: Aug. 9, 1972 [21] Appl. No.: 279,224

[76] Inventor:

[56] References Cited UNITED STATES PATENTS 3,174,464 3/1965 Johnson122/335 B 3,310,036 3/1967 Frendberg et al..... 110/49 R 3,618,22711/1971 Breckell et al 34/164 3,486,841 12/1969 Betz 34/35 3,692,2859/1972 Avery 432/79 447,155 2/1891 Krottnaurer... 432/90 1,304,5145/1919 Schmatolla 432/79 2,958,298 11/1960 Mayers l10/28.5 3,703,86111/1972 Slack et a1. 34/164 3,466,021 9/1969 Van Weert et a1. 432/583,104,955 9/1963 Marchand 34/168 2,703,936 3/1955 Hut 34/168 2,459,836l/1949 Manphree 122/4 D 2,498,710 2/1950 Roetheli 432/14 3,598,3748/1971 Nauta 432/58 i 3,795,987 [4 Mar. 12, 1974 907,575 12/1908 DeJongeet a1. 432/90 FOREIGN PATENTS OR APPLICATIONS I 61,629 11 1943 Denmark432/27 Primary Examiner-John J. Camby Assistant Examin'erl-lenry YuenAttorney, Agent, or Firm-Steinberg & Blake [57] ABSTRACT An apparatusfor treating material in bulk An upright bunker is provided toaccommodate the material in bulk while it flows gravitationally down theinterior of the bunker. The bunker has at its lower discharge end atapered wall formed with apertures to admit to the material in thebunker a gas at a temperature different from the material of the bunkerwhile permitting those parts of the material which are small enough topass through the apertures to fall out of the bunker through theapertures before reaching the lower discharge end. A plenum surroundsthe apertures and communicates with a gas supply through which the gasis delivered to the apertures to flow therethrough, and a gas dischargecommunicates with the top of the bunker to discharge the gas therefrom.The material falling through the apertures is collected in the plenumand conveyed away from the latter. Where the gas flowing up through thematerial in the bunker is heated by the latter material, a boiler mayreceive the hot gas from the bunker to use, the gas for generatingsteam, and the gas which is cooled in the boiler is then returned to theplenum.

16 Claims, 9 Drawing Figures COOLKNG OR PREHEATING DEVICE FCBR COARSE RBULKY MATERHAL HEAT SPACE RECOVERY EQUIPNENT BACKGROUND or THE INVENTIONThe present invention relates to devices for cooling or preheatingcoarse or bulky materials while being provided with heat-recoveryequipment.

' Devices of this general type are of course known at the present time.For example,in coke plants, it is conventional to situate the hot cokewhich discharges from the coke ovens in dry-quenching bunkers in which agas flows upwardly through the hot coke to extract heat therefrom Thecooled coke is discharged out of the bunkers and delivered to a suitablescreening station, for example.

Conventional apparatus of this type suffers from several drawbacks.Thus, it is conventional in dryquenching bunkers to introduce thecooling gas into the bunker by way of a pipe which communicates with agas distributor situated at the central axis of the bunker at asubstantial distance above the lower end thereof. The conventional gasdistributor has openings through which the gas escapes into the interiorof the bunker to contact the hot material therein, and these gasdischarge openings are surrounded by tapered baffles which serve todeflect the bulky material away from the gas discharge openings so thatthey will not become clogged. Such conventional structure of course actsto retard the downward flow of the bulky material in the bunker. Inaddition, the cooling gas which is delivered to the central axis of thebunker flows upwardly around the baffles and fails to come in contactwith the bulky material situated beneath the gas discharge openings aswell as beyond the immediate vicinity of the gas discharge openings atthe elevation of the latter. As a result, a considerable amount ofvaluable heat which might otherwise be carried away with the gas remainsin the bulky material so that the latter is not cooled in the mosteffective manner. I

Furthermore, bulky materials'of the above type will necessarily have ascomponents thereof relatively small particles in the form of dust orgranular bulky material, and these components are necessarily dischargedwith the remainder of the bulky material from the bunker. It is theseconditions which necessitate the use of a screening station where bulkymaterial composed of bodies only greater than a given size are sepa- 4rated from bodies smaller than this given size. These screeningoperations involve a considerable expense because of the apparatus andoperations in connection with the screening itself as well as because ofthe necessity of conveying the bulky material to and from the screeningstation.

In this latter connection, the conveying of the bulky material away fromthe bunker with all of the, components of the bulky material included inthe material which is conveyed creates a problem'in connection withrelease of dust and other pollutants to the outer atmosphere. it ispossible to use for this purpose special conveyers which do not releaseany dust to the outer atmosphere, but such conveyers are exceedinglyexpensive both to construct and to operate.

As was pointed out above, there is a considerable heat loss resultingfrom the fact that with conventional structures of the above type thecooling gas cannot available to be extracted from the hot coke. Ofcourse, 4

attempts are made to recover this energy by'directing gas heated in thebunker to heat exchangers, but nevertheless even with such arrangementsthere is a tremendous loss of heat which results from a number ofoperating factors which cannot be avoided with conventionalinstallations. Thus, one of the unavoidable large losses of heat resultsfrom heat loss through the wall of the bunker itself. Even with the bestavailable heat-. insulating techniques, the amount of heat energy whichis lost by simply being stored in the walls of the bunker andtransmitted therethrough to the outer atmosphere is tremendous.

. A second factor which contributes to unavoidable heat loss withconventional installations results from the relatively small parts ofthe bulky material which are separated from the larger parts thereof atthe screening station. A considerable amount of these smaller componentssimply float out into the atmosphere and not only pollute the atmospherebut waste heat which might otherwise be derived from these combustiblematerials. The remaining part of these smaller components of the bulkymaterial which are recovered at the screening station may of course beused for combustion, but in this case also additional costs are involvedin handling these smaller parts of the bulky material.

As has been indicated above, it is conventional to provide a closedcycle for gas according to which the gas flows upwardly through thebulky material in the bunker to extract heat from this material when itis hot and the gas is initially cool, and then the hot gas is directedthrough a steam generator to give up its heat in order to generatesteam, with the gas which is cooled in this way being returned to thebunker. With conventional installations of this type there areadditional heat losses resulting from the fact that the gas in theclosed cycle is not properly controlled so that the best possibleextraction of heat is not achieved. Furthermore, the gas which flows outof the bunker carries along a certain amount of dust from the bulkymaterial, and this dust deposits on the exterior surface ofheatexchanging elements preventing the latter from operating with thegreatest possible efficiency and necessitating undesirably largemaintenance costs, so that these latter factors also contribute toundesirable heat losses.

In addition to the economic drawbacks resulting from wasting of heatenergy, as set forth above, and environmental drawbacks resulting fromunavoidable pollution of the atmosphere with conventional installa-'.regularly occurring breakdowns of the equipment. It is never known whenpart of .the equipment will be rendered inoperative because of failureswhich are unexpectedly encountered, and it is therefore customary forplants of this type to provide installations where standby equipment isalways on hand to be set into operation when breakdowns are unexpectedlyencountered. These factors also contribute undesirably to the largecosts which are involved in the operation of such plants.

SUMMARY OF INVENTION It is accordingly a primary object of the presentinvention to provide an installation capable of handling bulky materialin such a way that many of the above drawbacks are eliminated whileothers are sharply reduced either in the frequency of their occurrenceor in magnitude.

Thus, one of the primary objects of the present invention is to providea bunker installation capable of handling bulky material'in such a waythat parts of the bulky material which are smaller than a given size areseparated from the bulky material even before the latter is dischargedfrom the bunker so that in this way it becomes possible to eliminatescreening operations and thus avoid all of the costs and disadvantagesnecessitated by the screening operations.

It is a further object of the present invention to provide for handlingof the smaller parts of the material separated from the bulky materialat the bunker itself in such a way that these smaller parts of the bulkymaterial will not pollute the outer atmosphere and can be economicallyand effectively utilized at suitable burners which make use of the heatenergy of these materials which otherwise would be wasted.

Yet another object of the present invention is to provide aninstallation of the type in which precise highly effective controls ofthe gas in a closed cycle are achieved in such a way as to provide thebest possible utilization of the available energy.

Furthermore, it is an object of the present invention to provide aconstruction of the above type which greatly reduces heat losses such asthose which are encountered at the present time with conventionalbunkers. This is an extremely important object of the present invention.

Moreover, it is an object of the present invention to provide aninstallation of the above type which for the amount of energy which. isextracted requires far less space than has heretofore been possible withconventional constructions.

I An additional object of the invention is to provide an installation ofthe above type which will enable operations to continue even if part ofthe structure must be taken out of operation because of a failure whichmay be encountered during the operation.

Also, it is an object of the present invention to provide for aninstallation of the above type safety components which on the one handgreatly reduces the possibility of explosions and on the other handprovide relatively safe conditions even in the rare instance when anexplosion may occur..

The objects of the present ivention also include the provision of aninstallation of the above type which is of a relatively light weight,providing considerable savings in foundation costs and the like, whileat the same time being exceedingly robust so that strength in theconstruction is combined with the light weight thereof.

Also, the objects of the invention include the provision of convenientand effective controls which make it possible to regulate the operationof an installation of the above type in a manner which will achieve thegreatest possible efliciency and heat recovery for the particularconditions which are encountered during operation.

According to the invention an apparatus for treating material in bulkincludes an upright bunker means which has an upper receiving end forreceiving the material in bulk and a lower discharge end through whichthe material in the bunker means discharges out of the latter whileprogressing gravitationally downwardly along the interior of the bunkermeans. The bunker means has in the region of its lower discharge end atapered wall portion the larger end of which is higher than its opposedsmaller end. This tapered wall portion of the bunker means is formedwith a plurality of apertures distributed throughout the tapered wallportion for admitting gas into the bunker means to flow upwardly throughthe bulky material therein while those parts of the bulky material whichare small enough to pass through the apertures will fall through thelatter apertures out of the bunker means before reaching the dischargeend thereof. A plenum means surrounds the tapered wall portion of thebunker means and a gassupply means communicates with the interior of theplenum means for supplying to the latter gas at a temperature differentfrom the bulk material to flow through the apertures into the bunkermeans and upwardly through the bulky material therein to achieve aheat-exchange relationship between the bulk material and the gas flowingupwardly therethrough. The parts of the bulky material which fallthrough the apertures are collected in the plenum means. A gas dischargemeans communicates with the interior of the bunker means at the regionof its upper receiving end to receive the gas which flows upwardlythrough the bulk material and to discharge the gas out of the bunkermeans. A transporting means communicates with a lower region of theplenum means to transport away from the latter those parts of the bulkmaterial which fall through the apertures before reaching the dischargeend of the bunker means.

BRIEF DESCRIPTION OF DRAWINGS I The invention is illustrated by way ofexample in the accompanying drawings which form part of this appli- FIG.3 is a schematic sectional plan view taken along line 3-3 of FIG. 1 inthe direction of-the arrows showing further details of the structure foradjusting the shiftable plate of FIG. 2;

FIG. 4 is a schematic elevation of the structure of FIG. 3;

FIG. 5 is a schematic sectional elevation of a preferred embodiment ofan installation according to the invention;

FIG. 6 is a schematic fragmentary sectional illustration of details ofthe boiler structure of FIG. 5;

FIG. 7 is a schematic partly sectionaly plan view of the installation ofFIG. 5 taken along line 77 of FIG. 5 in the direction of the arrows;

FIG. 8 is a schematic sectional plan view taken along line 88 of FIG. 5in the direction of the arrows and showing details of the structure foradjusting an outer apertured wall of FIG. 5; and

FIG. 9 is a fragmentary schematic representation of the plenum of FIG. 5and the transporting means for carrying material away from the plenum.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIG. 1, there isillustrated therein an upright bunker means 10 which is supported in anysuitable way on an unillustrated foundation and which has a wallcomposed of an outer steel casing l2 which is lined at its interior witha brick lining 14. The upright bunker means 10 has an upper receivingend 16 which receives the bulky material 20 which enters into theinterior of the bunker means 10. The upper receiving end 16 may includea central tube 22 into which the bulky material 20 is delivered asschematically indicated by the arrows 24. This material may be deliveredto the receiving end 16 from any suitable conveyer, chute, duct, or thelike. The bulky material 20 may take the form of incandescent coketransported dision 58 is capable of being opened and closed by asuitrectly from a coke oven, or it may be in the form of sinter or anyother coarse hot material.

As will be apparent from the description below, a gas which is heated bythe hot bulky material 20 flows upwardly through this material in theinterior of the bunker, and this gas is'received by a gas-dischargemeans 26 situated at the upper receiving end of the bunker and throughwhich the inlet pipe 22 extends. The gas discharge means 26 has a lowerwall 28 formed with apertures through which the gas enters the space 30between the wall 28 and the top wall 32- of the bunker. This space 30surrounds the pipe 22 and communicates with a pipe 34 through which thegas flows away from the bunker in the manner indicated by the arrows 36.For safety purposes the top wall 32 is provided with one or moreexplosion doors 38, one of which is schematically indicated in FIG. 1.

The upright bunker means 10 has a lower discharge end 40. This lowerdischarge end of the bunker is controlled by way of a suitablehorizontal gate 42 shiftable to the right and left, as indicated by thearrow 44 and operatively connected through a suitable rod 46,schematically indicated in FIG. I, to the piston of a hydraulic drive 48mounted on a support 50 carried by the framework of the bunker at theexterior of the latter. Thus the hydraulic motor 48 may be operated toact through the rod 46 on the gate 42 in order to open or close thedischarge end 40 of the bunker to a desired extent.

able gate 60 which is in turn controlled by a hydraulic drive 62.Through these several gates and their hydraulic drives it is possiblefor the bulky material, after progressing gravitationally down throughthe bunker 10, to reach a conveyer means 64 which conveys the bulkymaterialto any desired location such as suitable storage bunkers wherethe material is stored for future use.

In accordance with one of the important features of the presentinvention, the upright bunker means 10 includes a tapered wall portion66 which has its larger end 68 located higher than its smaller end 70.The smaller end 70 of the tapered wall portion 66 of the bunker 10terminates directly at the lower discharge end 40 of the bunker whilethe larger upper end 68 of the tapered wall portion 66 is joined thelower end of the bunker wall which is formed by the steel casing 12 andthe brick lining 14. The tapered wall portion 66 is formed with a'plurality of apertures 70 distributed throughout this tapered,frustoconical wall portion 66.

The tapered wall portion 66 is surrounded by a plenum means 72 whichdefines a closed interior chamber 74 which communicates with theapertures 70. The plenum means 72 in turn communicates with a gassupplymeans 76 through which gas at a suitablepressure is supplied to theinterior 74 of the plenum means 72, and this gas is capable of flowingthrough the apertures 70 of the tapered wall portion 66 into the bunkerin order flow upwardly through the bulky material 20 therein. The flowof the gas into the apertures from the interior 74 of the plenum means72 is indicated by the arrows 78. I

A number of advantages are achieved by way of this construction. Thus,the entry of the gas through the apertures 70 of the tapered wallportion 66 enables the gas to come into contact with the entire body ofbulky material which progresses gravitationally down the interior of thebunker, so that where the gas is a cold gas and the bulky material 26)is a hotmaterial, the cold will come in contact with all of the bulkymaterial and extract from the bulky material far more heat than hashitherto been possible with conventional installations.

However, an additional very great advantage which is achieved with thisconstruction is that those parts of the bulky material 20 which aresmall enough to pass through the apertures 70 will fall downwardlythrough these apertures into the interior of the plenum means 72 beforereaching the lower discharge end 40 of the bunker means 10. As a resultthe bulky material which is received by the conveyer means 64 issubstantially free of any'components small enough to fall through theapertures 70. The result is that screening actually takes place at theseapertures 70 and it becomes unnecessary for the conveyer means 64 toconvey the bulky material to a screening station.

The lower portion of the plenum means 72 is in the form of a series ofhoppers circumferentially distributed about the vertical axis of thebunker means 10, these hopper portions 80 being schematically indicatedin part in FIG. 9. The rod 46 extends between a pair of these hopperportions, and the hopper 52 is supported by beams which also extendbetween the hopper portions to be connected to the upper region of theplenum means 72.

Thus, the relatively small portions of the bulky material which aresmall enough to pass through the apertures 70 will collect in the plenummeans 72 at the lower ends of the several hopper portions 80 thereof. Asis apparent from FIG. 9 these hopper portions 80 communicate with apneumatic header 82, having a series of branches 83 communicatingrespectively with the several hopper portions 80. Thus, the header 82also extends circumferentially around the axis of the bunker and is of acircular configuration. As is indicated schematically in FIG. 9, thepneumatic header 82 communicates with a pipe 84 having a control valve86 and communicating with the inlet of a blower 88 which serves toprovide a stream of air conveying the small components of the bulkymaterial away from the plenum means 72 and delivering this material in astream of air along the pneumatic duct 90. As will be apparent from thedescription which follows this duct communicates with one or moreburners where the combustible material collected in the plenum means 72may be burned so as to utilize the heat energy thereof, and in additionthe deposition of the smaller components of the bulky material in theplenum means 72 prevents this smaller material, particularly thecomponents thereof which have the size of dust particles, from beingreleased to the outer atmosphere so that undesirable pollution of theouter atmosphere is avoided in this way.

Depending upon the conditions which are encountered it is desirable tocover and uncover the apertures 70 to a given extent. Some of theapertures 70 are illustrated on an enlarged scale in FIG. 2. Theseapertures may have a diameter on the order of inch, so that allcomponents of the bulky material which have a size a of k inch or lesswill fall through the apertures 70 to be received by the transportingmeans formed by the pneumatic pipe 82 and the blower 80. For somepurposes it may be desirable to cover the apertures 70, or

to partially uncover the apertures 70, and for this purthroughapproximately 90 about the axis of the bunker with the tapered wallportion 66 carrying T-guide strips 96 which are situated between andoverlap the sideedges of the vertically shiftable components of theouter wall means 92. These several cone sections of the outer wall means92 are respectively connected through suitable rods 98 with fourhydraulic drives 100, two of which are apparent from FIG. 1, andd thesehydraulic drives are mounted on suitable supporting frames carried bythe bunker at the exterior thereof. Through suitable controls thehydraulic drives 100 can be actuated to shift the several conesectionsof the outer wall means 92 upwardly or downwardly through the smallextent required to bring about complete covering or uncovering of theapertures or partial covering thereof. In this way it is possible tocontrol, for example, the speed with which the gas flows into the bunkerto contact the bulky material 20 therein. If it is desired to maintainin the bulky material which reaches the conveyer means 64 all componentswhich are larger than V4 inch, for example, then the hydraulic drives100 are operated so as to permit only components of the bulky materialwhich are smaller than flinch to fall through the apertures 70. Howeversuch an adjustment may be made up to a maximum size of a inch in theillustrated example.

The gas discharge means 26 delivers the gas at the upper receiving end16 of the bunker means 10 through the pipe 34 to the top end of a boiler102 which is schematically illustrated in FIG. 1 to the right of theupright bunker means 10. The schematically illustrated boiler 102includes an upper bank of coils 104 forming a superheater andcommunicating with a steam drum 106 in a well known manner. Below thesuperheater coils 104. are banks-of evaporator coils 108, and thelowermost bank of coils 108 forms a circulation evaporator receivingfeed water from a pipe 1 10, as schematically indicated in FIG. 1. Thelowest bank of coils 112 of the boiler 102 forms a gas preheater. Thepipe 76 receives the gas from the lower end of the boiler 102 anddelivers it to the plenum means 72. The pipe 76 may communicate with asuitable blower which serves to maintain the gas flowing through theabovedescribed closed cycle. The several banks of coils in the boiler102 may besurrounded by an outer welded assembly of tubes forming awatertube wall 1 14 of the boiler 102. Of course the several banks ofcoils and the watertube wall communicate with each other to provide forflow of water therethrough in order to achieve at the coils 104 thesuperheated steamwhich discharges out of the latter through the pipe 116which delivers the steam to any desired location where further use ismade thereof. Thus, this steam may be used to drive a turbine which inturn may drive a generator,

for example.

The pipe 34 accommodates in its interior, just upstream of the boiler102 an auxiliary burner 118 which is shown schematically in FIG. 1. Thisburner is provided to control the inert gas which flows through theclosed cycle described above. By way of suitable gas quality monitoringequipment the auxiliary burner 118 is regulated, and the pneumatic pipeof the conveyer means which conveys the particles collected in theplenum means 72 may ,deliver the combustible material to the auxiliaryburner 1 18 so that the energy of this collected material may be used atthe burner 1 18. This burner 118 also may be used for increasing thetemperature of the boiler at the region of the superheater coils 104, soas to regulate the quality of the steam which is delivered to the pipe116 from the bank of coils 104.

While it is possible with the installation of the invention describedabove to achieve many of the advantages of the present invention suchas-prevention ofpollution of the outer atmosphere, control of thecirculating gas of the closed cycle, and making use of available heatwhich otherwise would be wasted, it is possible to further improve theinstallation to eliminate certain advantages which are inherent in thisembodiment. Thus, with the embodiment of FIG. 1 there is still aconsiderable heat loss through the bunker wall structure. Thus the steelcasing 12 and its brick lining 14 will store a certain amount of heatwhich is wasted, and this heat is simply transferred to the outeratmosphere through the brick lining 14 and the steel casing 12. Thisheat loss amounts to l6-20 percent of the available heat, so that thereis a substantial loss through this type of construction.

Furthermore, the arrangement of the boiler 102 outside of the uprightbunker means 10 creates the necessity for floor space in addition tothat required by the bunker itself, so that an undesirably large amountof space is occupied by the installation which is shown in FIG. 1. Inaddition, the steel casing and brick lining of the bunker wall makes thebunker exceedingly heavy so that a very strong foundation is required.

'FIGS. 58 illustrate an embodiment of the invention which avoids thesedrawbacks of the embodiment of FIGS. 1-4. The upright bunker means 120shown in FIG. 5 also includes a lower tapered wallportion 66 providedwith apertures 70, this part of the structure being identical with thatof FIG. 1. Also, the lower tapered wall portion 66 of the bunker means120 is surrounded by a plenum means 72 which is substantially identicalwith that of FIG. 1. In addition, .the structure beneath the lowerdischarge end 40 of the bunker for receiving the bulky material from thebunker and conveying it to a suitable location is substantiallyidentical with that of FIG. 1 and is indicated by the same referencecharacters. The only difference is that pairs of gates 42 and 54 aremoved equally and oppositely by motors 48 and 56, respectively.

At the upper receiving end of the bunker means 120 the material entersalso through a pipe 22, and the gas discharges out of the bunker throughan apertured wall 28.

However, with this embodiment the boiler 122 directly surrounds thebunker and in fact has an inner water-tube wall 124 which forms thatpart of the bunker wall which extends upwardly from the tapered wallportion 66 thereof. The inner watertube wall of the boiler 122 not onlyreceives heat directly from the material 20 in the bunker itself, butpart of this wall extends downwardly beyond the top end of the taperedwall portion 66 so' that the lower portion of the inner watertube wall124 is heated by heat which travels through the lower tapered wall 66and is situated in the upper part of the plenum means 72.

The boiler 122 includes an outer watertube wall 126 which communicateswith the upper boiler drum 128 which may have an annular configuration.

In the space which is defined by the inner and outer watertube walls 124and 126 of the boiler 122 there are banks of convection coils 130. Thesebanks of convection coils 130 are arranged in the manner illustrated inFIG. 7 in separate groups of coils which are separately supplied throughcold water inlet pipes 132 and separately communicate with steamdischarge pipes 134 which communicate with the boiler drum 128. Thewatertube wall 126 is made up of a series of flat sections releasablyconnected to vertical spacers 127' of wedge shaped cross section to formthe polygonal configuration illustrated in FIG. 7, and as a result it ispossible if any one of the banks of coils 13G), fixed as by welding tothe flat sections of wall 126, respectively, becomes defective to removethis bank with the section of wall 126 fixed thereto while theoperations go forward with the other convection coil units 130. Spacers127 are formed with vertical passages 129 receiving feedwater from pipes132 and communicating with pipes 134.

The steam delivered through the pipes 134 to the boiler drum 128 flowsfrom the latter through pipes 136 into a series of superheating coils138 situated between the walls 124 and 126 above the convection coils130. superheated steam is discharged out of the superheating coils 138by way of the discharge tubes 141).

With the embodiment of FIG. 5, the lower wall portion 66 is surroundedby a tapered apertured wall 142 illustrated in F IGS. 5 and 8 and havingapertures corresponding to the apertures 94. These apertures 94 are alsocapable of registering with the apertures when the latter are completelyuncovered. The tapered wall 142 which matches the configuration of thetapered wall 66 and engages the latter at its exterior surface isslidable around the axis of the bunker for adjusting the extent to whichthe openings or apertures 70 are covered or uncovered. For this purposethe outer wall means 142 of this embodiment is fixed with a radiallyextending arm 144 connected through a rod 146 with a hydraulic drive148. The rod 146 may extend through suitable fittings of the plenummeans 72.

The gas flowing upwardly beyond the bulky material 20 in the bunkermeans of FIG. 5 flows through the apertures of the wall 28 into the gasdischarge means 26 of this embodiment. In this case also the top wall ofthe bunker is provided with an explosion door 38. In addition, thesafety is increased by connecting safety valves 147 to the boiler drum128. Just before the gas in the gas discharge means 26 reaches the topend of the space defined between the inner and outer watertube walls 124and 126 of the boiler 122, the gas encounters a dust collecting meansformed by inclined baffles or the illustrated series 150, and thus dustis prevented from entering into the boiler 122. This dust will entersuction pipes 151 communicating with cyclones 151), respectively, andwith a circular header 153 which communicates with header 82 (FIG. 9) tobe carried away by the transporting means shown in FIG. 9 and describedabove. Wall 155 carries the cyclones and fills the spaces therebetweenso that all gas from discharge means 26 must pass through cyclones 150.From'the latter, the cleaned hot gas flows through pipes 147 downwardlythrough the boiler.

The interior of the gas discharge means 26 also accommodates auxiliaryburners 152' which may be supplied by the pneumatic pipe 90, as frombranches 90a and 90b thereof so that the material collected in theplenum means may be burned at these auxiliary burners 152. The burnergas may also be derived from green coke with the addition of oxygen ifnecessary and with the admission of nitrogen if necessary to preventexplosions.

From drum 128 water flows down the tubes of watertube wall 126 and upthe tubes of watertube wall 124 to flow through circular header 121 intoa small number of widely spaced tubes 123 which respectively communicatewith the outer ends of a number of flat spiral tubes which form the top,wall 127. The inner ends of tubes 125 communicate through tubes 127 withdrum 128, thus completing the closed circuit through the boiler walls.

The watertube walls may be covered with Gunnite which is sprayed thereonin the form of a ceramic spray deposited on the fins and coils of thewatertube .walls to increase the heat resistance thereof. In addition itis possible to surround these watertube walls at their interior andexterior surfaces with heat-resistant steel plates or cast iron may beused if desired.

As may be seen from FIG. 6, it is also possible to fix the coils such asthe convection coils 130 directly to the watertube walls 124 and 126, sothat in this case an exceedingly strong construction will result withthe fixing of the interior coils to the inner and outer watertube wallsforming the same effect as a girder construction where beams arereinforced by struts extending between and fixed to the beams. The coilsmay be welded to the inner and and outer watertube walls or they may bebolted thereto in the manner shown schematically in FIG. 6. The samefixing of the coils to the inner and outer watertube walls may beprovided for the superheater coils 138. In this way while the entireboiler structure of FIG. is lighter than the brick lined steel wall ofFIG. 1, nevertheless it is exceedingly strong, and at the same time thefoundation for the embodiment of FIG. 5 need not be as strong as thefoundation required for the embodiment of FIG. 1.

Thus, FIG. 5 shows a strong but relativelylight supporting framework 154which carries the entire installation of FIG. 5. 1

According to a further feature of the invention this framework 154carries a vibrator means formed by a plurality of vibrators 156 in theform of suitable electrical motors carrying rotary discs provided witheccentric weights so that when the motors are operated a controlledvibration for the entire assembly will be provided. Through thisvibrator means 156 it is possible to increase the extent to which therelatively small components of the bulky material drop through theapertures 70 into the plenum means 72.

Thus, with the above-described structure of the invention it is possibleto cool or preheat course material through an orifice plate-type bunkerso that the most uniform gas flow through the bulky material isachieved. The elimination of dust from the bulky material before itreaches the discharge of the bunker means has the great advantage ofcreating less problems at a screening station if the material from thebunker is delivered to a screening station and in fact renders in manycases screening stations superfluous.

The collected dust may be used at the auxiliary burners, as pointed outabove, before the waste heat boiler and/or gas preheater. Theseauxiliary burners have the.

double function of increasing the steam production at the boilers andcontrolling the gas condition in the closed cycle.

The embodiment of FIG. 5 is of particular advantage because it is lightand at the same time strong and in addition requires far less floorspace than the embodiment of FIG. 1. The strength of the installation isgreatly increased by the fixing of the inner coils of the boiler to theinner and outer watertube walls thereof so that there is a stiffeningbetween these walls providing the effect of a box girder in a bridge. Inaddition, the exterior watertube wall 126 fixedly carries stiffeningrings 160 which are brazed directly onto the exterior watertube wall andserve to add to the stiffness and strength of the entire structure. Thisadded stiffening also increases safety in the case of an explosion.

Particularly with the embodiment of FIG. 5, loss of heat is reduced to aminimum. A minimum surface is exposed to the open air with'theembodiment of FIG. 5, so that an extremely large amount of heat canbeused for power generation or gas preheating. With the embodiment of FIG.5, because the heat lossesare' reduced to a minimum, the outsidewatertube wall temperature will not exceed 400 F, and of course withproper insulation which is provided the heat losses are reduced to anabsolute minimum.

A pipe system 76 similar to that of FIG. 1 receives cool gas from theboiler and delivers it to the plenum means 72.

What is claimed is:

1. In an apparatus for treating material in bulk, upright bunker meansthrough which the material to be treated is adapted to move in adownward direction, the material in bulk being in a heated conditionwhen received in said bunker means at an upper portion thereof and in acooled condition when discharging from said bunker means through a lowerportionthereof, gas supply means communicating with said lower portionof said bunker means for supplying a gas at a relatively low temperatureto flow upwardly through said bunker means to be heated by the materialin bulk therein by extracting heat therefrom while the material in bulkis cooled by the upwardly flowing gas prior to discharge of the materialin bulk from the lower portion of said bunker means, gas-discharge meanscommunicating with said upper portion of said bunker means fordischarging from the latter a hot gas heated by the material in bulkwhile the latter is cooled by the gas flowing upwardly through saidbunker means, and upright boiler means operatively connected between andcommunicating with said gasdischarge means and said gas-supply means forreceiving hot gas from said gas-discharge means and generating steamtherefrom while cooling the hot gas and for delivering cooled gas tosaid gas-supply means to be recirculated by the latter upwardly throughsaid bunker means for operating with heat from the material in saidbunker means.

2. In an apparatus for treating material in bulk as recited in claim 1,said bunker means having an upper receiving end for receiving thematerial in bulk and a lower discharge end through which the material insaid bunker means discharges out of the latter while progressinggravitationally downwardly along the interior of said bunker means, saidbunker means having in the region of said discharge end thereof atapered wall portion the larger end of which is higher than its opposedsmaller end, said tapered wall portion of said bunker means being formedwith a plurality of apertures distributed throughout said tapered wallportion for admitting gas into said bunker means to flow upwardlythrough the bulky material therein while those parts of the bulkymaterial which are small enough to pass through said apertures will fallthrough the apertures out of the bunker means before reaching saiddischarge end thereof, plenum means surrounding said tapered wallportion of said bunker means and said gas-supply means communicatingwith the interior of said plenum means for supplying to the latter gasto flow through said apertures into said bunker means and upwardlythrough the bulk material therein to achieve a heatexchange relationshipbetween the bulk material and the gas flowing upwardly therethrough, theparts of the collected bulky material which fall through said aperturesbeing in said plenum means said gas discharge means communicating withthe interior of said bunker means at the region of said upper receivingend thereof for receiving the gas which flows upwardly through the bulkmaterial and for discharging the gas out of said bunker means, and intosaid boiler means, and transporting means communicating with a lowerregion of said plenum means for transporting away from the latter thoseparts of the bulk material which fall through said apertures beforereaching said discharge end of said bunker means.

3. The combination of claim 2 and wherein an outer wall means is locateddirectly next to said tapered wall portion of said bunker means inengagement therewith and is formed with apertures which in one positionof said outer wall means respectively register with said apertures ofsaid tapered wall portion, and adjusting means operatively connectedwith said outer wall means for adjusting the position thereof withrespect to said tapered wall portion for controlling the extent to whichsaid apertures of said tapered wall portion are covered or uncovered bysaid outer wall means.

4. The combination of claim 1 and wherein said boiler means is spacedfrom said bunker means.

5. The combination of claim 4 and wherein said bunker means includesabove said tapered wall portion thereof an outer steel casing and aninner brick lining covering the interior surface of said steel casing.

6. The combination of claim 2 and wherein said boiler means directlysurrounds and is carried by said bunker means, part of said boiler meansforming a wall of said bunker means which extends upwardly from saidtapered wall portion thereof.

7. The combination of claim 1 and wherein said boiler means directlysurrounds and is carried by said bunker means, part of said boiler meansforming a wall of said bunker means and said wall of said bunker meanswhich is formed by part of said boiler means being a watertube wallforming an inner wall of said boiler means, said boiler means includingan outer watertube wall spaced from and surrounding said inner watertubewall thereof which forms part of said bunker means, and convection coilsextending between and fixed at least to said outer watertube walls ofsaid boiler means for forming a substantially rigid tubular assemblytherewith, said inner and outer watertube walls defining betweenthemselves a space in which said convection coils are accommodated andsaid space having an upper end region communicating with saidgas-discharge means to receive the hot gas therefrom and a lower endregion communicating with said gas-supply means for supplying cool gasthereto.

8. The combination of claim 7 and wherein a dustcollector means issituated between said gas-discharge means and said upper end region ofsaid boiler means for preventing dust from entering said boiler meanswith the hot gas delivered to said boiler means by said gas-dischargemeans.

9. The combination of claim 7 and-wherein a burner means is situated insaid gas-discharge means for increasing the steam production of saidboiler means and for controlling the gas condition in the closed cycledefined by said bunkermeans, boiler means, and gassupply and dischargemeans.

10. The combination of claim 9 and wherein a transporting meanstransports the material collected from said bunker means away from thelatter to said burner means to be burned thereby.

'11. The combination of claim 7 and wherein said convection'coils aredivided into separate banks which are separately removable so that ifnecessary one of said banks can be removed while operations continuewith the remaining banks.

12. The combination of claim 2 and wherein said transporting means is inthe form of a pneumatic rneans communicating with the lower region ofsaid plenum means for transporting material out of the latter in astream of air.

13. The combination of claim 12 and wherein a valve means is situatedbetween said plenum means and pneumatic means for controlling the flowof material from said plenum means to said pneumatic means.

14. The combination of claim 2 and wherein a vibrator means isoperatively with said bunker means means for vibrating the latter topromote the falling of part of the bulk material through said apertures.

15. The combination of claim 2 and wherein a conveyer means is situatedin part beneath said discharge end of said bunker means for receivingthe bulk material therefrom and for conveying the bulk material awayfrom said bunker means, whereby screening of the material carried bysaid conveyer means is rendered unnecessary because of the falling ofpart of the bulk material through said apertures.

16. The combination of claim 1 and wherein said boiler means directlysurrounds said bunker means and boiler means having a common. watertubewall.

1. In an apparatus for treating material in bulk, upright bunker meansthrough which the material to be treated is adapted to move in adownward direction, the material in bulk being in a heated conditionwhen received in said bunker means at an upper portion thereof and in acooled condition when discharging from said bunker means through a lowerportion thereof, gas supply means communicating with said lower portionof said bunker means for supplying a gas at a relatively low temperatureto flow upwardly through said bunker means to be heated by the materialin bulk therein by extracting heat therefrom while the material in bulkis cooled by the upwardly flowing gas prior to discharge of the materialin bulk from the lower portion of said bunker means, gas-discharge meanscommunicating with said upper portion of said bunker means fordischarging from the latter a hot gas heated by the material in bulkwhile the latter is cooled by the gas flowing upwardly through saidbunker means, and upright boiler means operatively connected between andcommunicating with said gas-discharge means and said gas-supply meansfor receiving hot gas from said gas-discharge means and generating steamtherefrom while cooling the hot gas and for delivering cooled gas tosaid gas-supply means to be recirculated by the latter upwardly throughsaid bunker means for operating with heat from the material in saidbunker means.
 2. In an apparatus for treating material in bulk asrecited in claim 1, said bunker means having an upper receiving end forreceiving the material in bulk and a lower discharge end through whichthe material in said bunker means discharges out of the latter whileprogressing gravitationally downwardly along the interior of said bunkermeans, said bunker means having in the region of said discharge endthereof a tapered wall portion the larger end of which is higher thanits opposed smaller end, said tapered wall portion of said bunker meansbeing formed with a plurality of apertures distributed throughout saidtapered wall portion for admitting gas into said bunker means to flowupwardly through the bulky material therein while those parts of thebulky material which are small enough to pass through said apertureswill fall through the apertures out of the bunker means before reachingsaid discharge end thereof, plenum means surrounding said tapered wallportion of said bunker means and said gas-supply means communicatingwith the interior of said plenum means for supplying to the latter gasto flow through said apertures into said bunker means and upwardlythrough the bulk material therein to achieve a heat-exchangerelationship between the bulk material and the gas flowing upwardlytherethrough, the parts of the bulky material which fall through saidapertures being collected in said plenum means said gas discharge meanscommunicating with the interior of said bunker means at the region ofsaid upper receiving end thereof for receiving the gas which flowsupwardly through the bulk material and for discharging the gas out ofsaid bunker means, and into said boiler means, and transporting meanscommunicating with a lower region of said plenum means for transportingaway from the latter those parts of the bulk material which fall throughsaid apertures before reaching said discharge end of said bunker means.3. The combination of claim 2 and wherein an outer wall means is locateddirectly next to said tapered wall portion of said bunker means inengagement therewith and is formed with apertures which in one positionof said outer wall means respectively register with said apertures ofsaid tapered wall portion, and adjusting means operatively connectedwith said outer wall means for adjusting the position thereof withrespect to said tapered wall portion for controlling the extent to whIchsaid apertures of said tapered wall portion are covered or uncovered bysaid outer wall means.
 4. The combination of claim 1 and wherein saidboiler means is spaced from said bunker means.
 5. The combination ofclaim 4 and wherein said bunker means includes above said tapered wallportion thereof an outer steel casing and an inner brick lining coveringthe interior surface of said steel casing.
 6. The combination of claim 2and wherein said boiler means directly surrounds and is carried by saidbunker means, part of said boiler means forming a wall of said bunkermeans which extends upwardly from said tapered wall portion thereof. 7.The combination of claim 1 and wherein said boiler means directlysurrounds and is carried by said bunker means, part of said boiler meansforming a wall of said bunker means and said wall of said bunker meanswhich is formed by part of said boiler means being a watertube wallforming an inner wall of said boiler means, said boiler means includingan outer watertube wall spaced from and surrounding said inner watertubewall thereof which forms part of said bunker means, and convection coilsextending between and fixed at least to said outer watertube walls ofsaid boiler means for forming a substantially rigid tubular assemblytherewith, said inner and outer watertube walls defining betweenthemselves a space in which said convection coils are accommodated andsaid space having an upper end region communicating with saidgas-discharge means to receive the hot gas therefrom and a lower endregion communicating with said gas-supply means for supplying cool gasthereto.
 8. The combination of claim 7 and wherein a dust-collectormeans is situated between said gas-discharge means and said upper endregion of said boiler means for preventing dust from entering saidboiler means with the hot gas delivered to said boiler means by saidgas-discharge means.
 9. The combination of claim 7 and wherein a burnermeans is situated in said gas-discharge means for increasing the steamproduction of said boiler means and for controlling the gas condition inthe closed cycle defined by said bunker means, boiler means, andgas-supply and discharge means.
 10. The combination of claim 9 andwherein a transporting means transports the material collected from saidbunker means away from the latter to said burner means to be burnedthereby.
 11. The combination of claim 7 and wherein said convectioncoils are divided into separate banks which are separately removable sothat if necessary one of said banks can be removed while operationscontinue with the remaining banks.
 12. The combination of claim 2 andwherein said transporting means is in the form of a pneumatic meanscommunicating with the lower region of said plenum means fortransporting material out of the latter in a stream of air.
 13. Thecombination of claim 12 and wherein a valve means is situated betweensaid plenum means and pneumatic means for controlling the flow ofmaterial from said plenum means to said pneumatic means.
 14. Thecombination of claim 2 and wherein a vibrator means is operatively withsaid bunker means means for vibrating the latter to promote the fallingof part of the bulk material through said apertures.
 15. The combinationof claim 2 and wherein a conveyer means is situated in part beneath saiddischarge end of said bunker means for receiving the bulk materialtherefrom and for conveying the bulk material away from said bunkermeans, whereby screening of the material carried by said conveyer meansis rendered unnecessary because of the falling of part of the bulkmaterial through said apertures.
 16. The combination of claim 1 andwherein said boiler means directly surrounds said bunker means andboiler means having a common watertube wall.